1. Field of the Invention
The present invention relates to a light emitting diode (LED) package having an improved heat dissipation efficiency, and more particularly, to a heat conducting slug having a multi-step structure, wherein a slug structure of an LED package is configured into a multi-step structure so that heat generated from a light emitting chip is efficiently dissipated, and an LED package using the heat conducting slug.
2. Discussion of the Background
In recent years, an interest in lighting devices using an LED chip tends to increase. In order to use such an LED for lighting purpose, luminous power over several thousand lumens (where 1 lumen is a luminous flux emitted from a light source of one candela per a unit solid angle) is required in addition to improved quality of light emission. Such a high power light emission is in proportion to the input current, so that high current may give a required luminous power. However, if the input current is increased, a large amount of heat is generated accordingly.
A large amount of heat generated from the light emitting chip has fatal influence on the life span of the light emitting chip. In order to solve the problem, an LED package having a heat dissipation member such as a slug is manufactured.
Conventionally, in order to improve a heat dissipation effect of a slug, there has been an attempt to change the material and size of the slug. However, there is a limit in changing the material and size of the slug, and thus, other studies for enhancing a heat dissipation effect of a slug are needed.
Meanwhile, among conventional LED packages, there is an LED package having a molding member formed by casting molding, wherein a molding member is formed by mounting a slug in a housing, bringing an additional mold into close contact therewith while a light emitting chip is mounted in the slug, and then injecting a liquid resin into the mold.
However, since the liquid resin is injected at high pressure into the mold in the conventional technique, the mold may not be in close contact with the housing but be separated due to the pressure in the mold. In a case where the mold is separated from the housing when the liquid resin is injected into the mold, the mold cannot be in close contact with the housing again, thereby making it impossible to form a molding member, which causes product failures. In addition, even though the mold is in close contact with the housing again, the liquid resin in the mold may leak out through a gap generated by the separation between the mold and the housing, thereby resulting in product failures.
In addition, in a case where a slug is mounted after the housing is formed, the slug is separated from the LED package, which may cause device failures. Such device failures cause disconnection of wire, which makes it impossible to use the LED package again. Thus, it is required to assemble a slug and a housing such that the slug is not separated from the LED package.